Trophic interactions as determinants of the arbuscular mycorrhizal fungal community with cascading plant-promoting consequences

Abstract

Background The soil mycobiome is composed of a complex and diverse fungal community, which includes functionally diverse species ranging from plant pathogens to mutualists. Among the latter are arbuscular mycorrhizal fungi (AMF) that provide phosphorous (P) to plants. While plant hosts and abiotic parameters are known to structure AMF communities, it remains largely unknown how higher trophic level organisms, including protists and nematodes, affect AMF abundance and community composition. Results Here, we explored the connections between AMF, fungivorous protists and nematodes that could partly reflect trophic interactions, and linked those to rhizosphere P dynamics and plant performance in a long-term manure application setting. Our results revealed that manure addition increased AMF biomass and the density of fungivorous nematodes, and tailored the community structures of AMF, fungivorous protists, and nematodes. We detected a higher abundance of AMF digested by the dominant fungivorous nematodes Aphelenchoides and Aphelenchus in high manure treatments compared to no manure and low manure treatments. Structural equation modeling combined with network analysis suggested that predation by fungivorous protists and nematodes stimulated AMF biomass and modified the AMF community composition. The mycorrhizal-fungivore interactions catalyzed AMF colonization and expression levels of the P transporter gene ZMPht1;6 in maize roots, which resulted in enhanced plant productivity. Conclusions Our study highlights the importance of predation as a key element in shaping the composition and enhancing the biomass of AMF, leading to increased plant performance. As such, we clarify novel biological mechanism of the complex interactions between AMF, fungivorous protists, and nematodes in driving P absorption and plant performance.

Phospholipid fatty acids in soil—drawbacks and future prospects

“…It should be further considered that G-bacteria contribute most likely only 10% to the total microbial biomass (Joergensen and Wichern 2008;Murugan et al 2021), i.e., markedly less than AMF (Faust et al 2017). For this reason, the neutral lipid fatty acid (NLFA) 16:1ω5 has sometimes been used as an AMF indicator (Jiang et al 2020) although NLFA do not solely occur in the biomass of organisms (Zelles 1999). Faust et al (2017) showed that PLFA 16:1ω5 and NLFA 16:1ω5 give similar information on the presence of AMF in soil and recommended solely using the PLFA as an indicator for AMF biomass.…”

Effects of Conventional and Organic Agriculture on Soil Arbuscular Mycorrhizal Fungal Community in Low-Quality Farmland

“…The high organic carbon content in organic amendments can promote the mycelial proliferation of AM fungi ( Hart and Reader, 2002 ), thus increasing the inoculation capacity of AM fungi on plant roots. Therefore, some studies found that colonization activity ( Qin et al, 2015 ; Jiang Y. J. et al, 2020 ) and AM fungal diversity ( Bhadalung et al, 2005 ; Lin et al, 2012 ) were higher on organic farms than on conventional farms. However, we hypothesize that these effects of conventional and organic farming systems on soil AM fungi may be different in low-quality farmlands for the following reasons.…”

Soil bacterial community triggered by organic matter inputs supports a high-yielding pear production

“…Structural equation modelling approach has been widely used to decipher keystone indicators associated with soil function and crop production in agroecosystems (Jiang et al, 2020;Chen et al, 2019).…”